How People Reacted:

There were various levels of interaction with the piece.  The two biggest reactions are to either drink or refill from the fountain and block the sensor to activate the projection, or to avoid the sensor, either by standing at the main fountain at a different angle or distance, or to just use the second fountain.  There were a couple of cases where people would actively experiment with the sensor, placing their hands over it to observe how the projection would react.  On the converse side, there was a person who in confusion pressed on the sensor itself, and surprised, used the other water fountain instead.

Before, we had a sticky note near the sensor telling people to not touch the electronics, but it was interpreted by others to mean to not touch the fountain.  We replaced it with a sticky saying "stand in front of me", but that also created a level of suspicion from the viewers.  Finally, after removal of the sticky entirely, we had the most interaction with the fountain.

Focusing on the process of interaction, for those who drank directly from the water fountain, the usual progression was that they would notice the effects, drink, notice the result of the sensor, and then test the sensor.